The Codex Committee on Pesticide Residues (CCPR), in its development of international standards, has been considering during the last few years the implications of residues of acutely toxic pesticides in food commodities. CCPR has asked its scientific advisory body, the Joint FAO/WHO Meeting on Pesticide Residues (JMPR), for advice on the safety of the standards that are being developed. This work began in 1993. The 1994 JMPR first decided to use the 'acute reference dose' as a toxicological benchmark for a 'short-term ADI'. A number of acute reference doses have been allocated at subsequent meetings. The 1998 JMPR decided to consider the allocation of an acute reference dose whenever a full evaluation of a pesticide is undertaken. General guidance for the allocation of an acute reference dose was provided by the 1998 JMPR, which is discussed in this paper.